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2017, Volume 31 Issue 05 Publication date: 26 May 2017 Previous Issue Next Issue

China Plastics Industry(2016)

2017, 31 (05): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2017.05.001

Abstract ( 674 )

General situation of China plastics industry in 2016 was reviewed, including the output, import and export of plastics products, as well as major economic data, such as the total industrial values, sales and profits of plastics products, etc. Analysis of the market of plastics products in 2016 was made, and the developing trend of China plastics industry in 2017 was proposed.

Application of 3D Printing Rapid Prototyping Technology in Processing of Polymeric Materials

2017, 31 (05): 6-12 ; DOI: 10.19491/j.issn.1001-9278.2017.05.002

Abstract ( 496 )

The article reviewed the influence of materials on the development of 3D printing rapid prototyping technology (3D printing technology) and industrialization process and also introduced the promoting effect of rapid development of polymeric materials on 3D printing technology and its industrial chain. The articles summarized the application of polymeric materials specially used for 3D printing rapid prototyping process in recent years. The application of 3D printing rapid prototyping technology in polymers, processing was introduced and its prospect was forecasted.

Study on Preparation and Properties of Copper-nanowire-based Transparent Conductive Film

2017, 31 (05): 13-17 ; DOI: 10.19491/j.issn.1001-9278.2017.05.003

Abstract ( 536 )

Copper nanowires were first synthesized through a liquid phase reduction method, and then the PVDF/copper nanowire thin films were prepared by using spray coating and wire rod coating technologies. The crystalline structure of copper nanowires was determined by X-ray diffraction measurements, and their morphology was characterized by scanning and transmission electron microscopy. The light transmittance and surface electrical resistance of the thin film was obtained by a UV spectrometer and a four-point probe method, respectively. The results indicated that the prepared copper nanowires had a diameter of approximately about 60 nm, a length of 60~80 μm and a high aspect ratio, and they exhibited a high purity and a good dispersion with the help of synergistic effect from inducing agent and stabilizing agent. The thin film achieved a maximum light transmittance of 61 % and manimum surface resistance of 40.7 Ω at the copper nanowire concentration of 0.08 mg/mL.

Analysis of Influencing Factors for Oxygen Permeability of Plastic Barrier Pipes

2017, 31 (05): 18-21 ; DOI: 10.19491/j.issn.1001-9278.2017.05.004

Abstract ( 572 )

The article reported the analysis of the influence factors for the oxygen permeability of oxygen barrier pipes, and these factors include the ethylene content of ethylene-vinyl alcohol copolymer (EVOH), the wall thickness of oxygen barrier layer and the processing temperatures. The results indicated that the lower the ethylene content of EVOH, the better the oxygen barrier performance.There was a correlation between the wall thickness of oxygen barrier layer and EVOH brand. Generally,the thickness of barrier oxygen layer thickness was in the range of 0.08~0.10 mm. There was no significant influence observed from the processing temperature of EVOH layer on the oxygen barrier performance of the pipes.

Study on Properties of Phthalocyanine End-capped Polyimide Film

2017, 31 (05): 22-25 ; DOI: 10.19491/j.issn.1001-9278.2017.05.005

Abstract ( 446 )

Phthalocyanine end-capped polyimide (PI) films were prepared through in-situ polymerization by using 4,4'-diaminodiphenyl ether and pyromellitic dianhydride as raw materials and 4-amino phthalocyanine copper as an end-capper, and their imidization degree, mechanical properties, thermal performance and optical properties were characterized by Fourier-transform infrared spectroscopy, universal testing machine, thermal mechanical analyzer and UV-Visible spectroscopy, respectively. The results indicated that the end cap by phthalocyanine could effectively control the macromolecular chains of PI. When the molecular weight was controlled to 20000, the film could keep good mechanical properties and high thermal stability, and its absorption in the visible region was broadened in the range of 600~650 nm.

Preparation and Performance of Silicone Rubber/Modified Montmorillonite Composites

2017, 31 (05): 26-30 ; DOI: 10.19491/j.issn.1001-9278.2017.05.006

Abstract ( 658 )

A surface modification for montmorillonite (MMT) was conducted by using di-octadecyl dimethyl ammonium chloride, and then the methyl vinyl silicone rubber (MVQ)-based composites with modified MMT and the pristine one were prepared by a melt mixing method. The effect of room temperature mixing and melting mixing methods on mechanical properties, thermal performance and morphology of the composites were investigated. The results indicated that the interlamellar spacing of MMT was improved from 1.25 to 3.97 nm after modification. The melt mixing method was more advantageous for the formation of intercalated structure in comparison with the room temperature mixing method. The composites prepared by melt mixing also achieved higher tensile strength, and a maximum value of 6.0 MPa when 30 phr of modified MMT was incorporated. However, its thermal stability tended to decrease.

Structure and Properties of PE-HD/MWCNTs Composites Prepared by Friction Stir Processing

2017, 31 (05): 31-35 ; DOI: 10.19491/j.issn.1001-9278.2017.05.007

Abstract ( 439 )

High-density polyethylene (PE-HD)/multiwalled carbon nanotubes (MWCNTs) composites are prepared through a friction stir processing method. The effect of traverse speeds on macro- and micro-structures and tensile strength of the composite was investigated. The results indicated that the composite layers exhibited a smooth surface without any defects. MWCNTs were uniformly dispersed in the matrix in a cloudy form. The lower traverse favors the separation and dispersion of MWCNTs in the matrix. The tensile strength exhibited a trend of increase at first and decrease afterwards with an increase of traverse speed, and a maximum value was achieved at the traverse speed of 30 mm/min.

Effects of Screw Rotation on Glass Fiber in Matrix and Properties of PP/GF Composites

2017, 31 (05): 36-41 ; DOI: 10.19491/j.issn.1001-9278.2017.05.008

Abstract ( 498 )

Polypropylene (PP)/glass fiber(GF)composites were prepared by a co-rotating twin-screw extruder, and the effect of screw rotation on GF in the composites and the properties of composites was investigated. The results indicated that the content of GF increased with an increase of rotation speed and achieved a maximum value of 48.2 %. However,the fiber length tended to decrease gradually with increasing rotation speed. The tensile strength, bending strength, heat-resistant temperature and hardness of the composites were improved with the increase of rotation speed, but the impact strength showed a slow decline. The incorporation of maleic anhydride-grafted PP improved the fiber length significantly, and meanwhile, the GF content, tensile strength, bending strength, notched and no-notched impact strength increased 1.8 %,95.1 %,90.1 %,50 % and 110.4 %, respectively.

Preparation and Properties of PP/POE Compounds Filled with Inorganic Particles

2017, 31 (05): 42-45 ; DOI: 10.19491/j.issn.1001-9278.2017.05.009

Abstract ( 426 )

Layered kaolin, granular CaCO3 and rodlike attapulgite (ATP) were employed as inorganic fillers, and then the polypropylene (PP)/poly(ethylene-co-1-octene) (POE) compounds filled with the three inorganic particles were prepared by melt extrusion. The mechanical properties, processability and microstructures of the resultant compounds were investigated by universal testing machine, impact testing machine, melt flow rate measurer and scanning electron microscopy, respectively. The results indicated that the tensile strength of the compounds achieved the maximum value of 29.1 MPa when 2.5 wt % of ATP was incorporated, whereas their notched impact strength reached the maximum value of 14.0 kJ/m2 at CaCO3 content of 2.5 wt %. In addition, the processability of PP/POE/CaCO3 compounds was improved significantly, which was attributed to the spherical CaCO3 particles acting as “ball bearings” in the matrix.

Study on Temperature Field of Blown Film Process for PLA and PE-LD in Certain Temperature Control System

2017, 31 (05): 46-51 ; DOI: 10.19491/j.issn.1001-9278.2017.05.010

Abstract ( 455 )

Temperature fields of bolwn film process for ploy(lactic acid) (PLA) and low-density polyethylene (PE-LD) in certain temperature control system were studied through a numerical simulation on the basis of some reasonable assumptions. The model was established by a Fluent software and then verified by the measured results from PE-LD. The results indicated that the simulated values of PE-LD were in good agreement with its measured results in the distance range of 70~110 mm. Although there were some errors in the distance range of 50~70 mm, the whole trend was identical. Summarily, the temperature fields can be predicted for the blowing process of PLA film under different parameter conditions via this simulation method, thus providing guidance for mass production and quality analyses.

Combined Optimization and 6Sigma Analysis of Processing Parameters for Car Dashboard Shells Based on Outside Mold Three-dimensional Filming Technology

2017, 31 (05): 52-56 ; DOI: 10.19491/j.issn.1001-9278.2017.05.011

Abstract ( 389 )

The forming process of car dashboard shells based on outside mold three-dimensional filming technology was simulated so as to make the film thickness distribution more uniform and improve the accuracy of deformation. The process parameters were designed and analyzed by a central composite design method on the basis of the design of experiments analysis and the establishment of Kriging model, and then they are optimized by a multi-objective optimization method combined with the global particle swarm optimization and the gradient sequential quadratic programming optimization. The optimization results were further analyzed by an average reliability method in terms of 6-sigma reliability. The results indicated that, after such optimization, the reduction ratio increased by 3.21 %, the maximum deformation in the x-direction decreased by 25.63 %, and the maximum deformation in the y-high reliability.

Study on Molecular Dynamics Simulation for Adsorption-diffusion Behavior of Gas Molecules in Packing Stage of Injection Molding

Hui WU, XIN Yong

2017, 31 (05): 57-64 ; DOI: 10.19491/j.issn.1001-9278.2017.05.012

Abstract ( 461 )

Six cell models of polystyrene (PS) chains including sotactic, syndiotactic and atactic single chains consisting of 40 repeating units were established. The equilibrium adsorption behaviors of O2/N2 in PS melt were analyzed by Monte Carlo method, and then diffusion behaviors of pure gases and their mixture in different PS melts were studied under a coupling effect of temperature and pressure with an introduction of Compass force. The results indicated that O2/N2 mixture improved the overall adsorption in different structural PS melts, but the adsorption capacity of pure gases was suppressed. The mixed gas also improved the gas diffusion capability in a certain extent. Moreover, the backbone activity and the size of gas molecular influenced the diffusion coefficient. The diffusion behaviors of O2/N2 presented a conversion from non-Einstein diffusion to the Einstein one and also exhibited a skip and cavity diffusion manner in PS melt.

Effect of Cell Space Lattice on Mechanical Properties of ABS Based on 3D Printing Process

2017, 31 (05): 65-70 ; DOI: 10.19491/j.issn.1001-9278.2017.05.013

Abstract ( 430 )

On the basis of the requirement of lightweight for 3D printed parts, geometric distribution models toward different cellular structure were established and classified. Then, three kinds of cell space lattice-structural specimens based on acrylonitrile-butadiene-styrene copolymer (ABS) were fabricated by 3D printing technology, and the relationship among their cell space lattice structure and porosity and tensile mechanical properties were investigated. The results indicated that three lattice-structural ABS samples presented different stress-strain curves in the same apparent density. Slopes of the three samples exhihited an increasing difference with an increase of apparent porosity increasing. There is great differnce between mechanical properties and sensitivity of porosity according to different lattice structures. With the increase of porosity, the elastic modulus of the sample with face-centered cubic structure decreased slowly; however, a rapid decline in elastic modulus was observed for the samples with the bodycentered cubic and corner-centered structures.

Optimal Design and Analysis of Pressure Holding Curve During Injection Molding Process

2017, 31 (05): 71-77 ; DOI: 10.19491/j.issn.1001-9278.2017.05.014

Abstract ( 454 )

To resolve the problem of excessive deformation generating in the injection-molded lower casing of temperature controller of an air conditioner, the lower casing was analyzed by a multi-response Taguchi method and then simulated by a Moldflow software. The results indicated that the optimum combination of processing parameters included a mold temperature of 60 ℃, a melt temperature of 230 ℃, a packing pressure of 60 MPa and a holding time of 20 s. The maximum warping deformation was significantly suppressed to decrease by 0.036 mm when the lower casing was injection molded with these optimum process parameters.

Stabilization of PP Against Thermal- and Photo-oxidation in Different Antioxidant Systems

2017, 31 (05): 78-83 ; DOI: 10.19491/j.issn.1001-9278.2017.05.015

Abstract ( 504 )

To impart a long-term antioxidant capability to polypropylene (PP), the hindered phenol antioxidants and hindered amine light stabilizers were selected as anti-aging agents to prepared the aging-resistant PP. The rheological and mechanical properties of the aging-resistant PP were evaluated, and the effects of antioxidants and light stabilizers on their aging properties were investigated. The results indicated that the hindered phenol antioxidants led to an enhanced antioxidation capability for PP parts in an order of Irganox 1076>Irganox 3114>Irganox 1330>Irganox 1010. A combination of Irganox 1076 and Chimassorb 944 could generate a long-term antioxidant effect on PP,the retention rates for elongation at break of PP were 75.9 % and 52.8 % after thermal oxidative aging for 72 h and 144 h, respectively. The retention rates for shear viscosity were 89.9 % and 74.1 % at the screw rotation rate of 1 r/min.

Preparation, Complex and Performance of Yttrium Fumaropimaric Acid as Thermal Stabilizer for PVC

2017, 31 (05): 84-91 ; DOI: 10.19491/j.issn.1001-9278.2017.05.016

Abstract ( 445 )

Yttrium fumaropimaric acid (YFPA) was synthesized by using fumaropimaric acid and yttrium acetate tetrahydrate as raw materials. Structure and morphology of YFPA was characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction measurements, and effect of YFPA as a heat stabilizer on thermal stability of poly(vinyl chloride) (PVC) was investigated by Congo red and oven thermal aging methods. The results indicated that the YFPA product presented an amorphous and three-dimensional network structure connected by the coordinate bond of COO- and Y3+. The duration of thermal stability for PVC could be extended to 21 min when 1 phr of YFPA was added. The complex of YFPA with alcium stearate, zinc stearate and pentaerythrite could more effectively improve the long-term thermal stability of PVC and also retard its stainability at the initial heating stage. When the weight ratio of YFPA and calcium stearate was set to 1.5:1, the duration of thermal stability of PVC was improved up to 62 min. Meanwhile, no color change was observed from PVC specimen within 20 min, and no black color was found within 80 min.

Design of Large-sized Injection Molds for Main Bodies of Auto Central Channels

张维合 allenzhang

2017, 31 (05): 92-97 ; DOI: 10.19491/j.issn.1001-9278.2017.05.017

Abstract ( 605 )

On basis of structural characteristics and appearance requirements for main bodies of auto central channels, a large-sized side core-pulling injection mold equipped by a hot runner system with two sequence valves was designed in terms of the design considerations and experiences of injection mold forming parts, side core-pulling mechanism, gating system, temperature control system, guiding system and stripping ejection system. Injection molding tests indicated that the mold was safe and stable during motion due to its reasonable structure, and its forming cycle and precision met the requirements for our design. The cast study demonstrated that the productivity increased by approximate 10 % when the forming cycle of the mold was controlled at about 60 s.

Design of Injection Molds for Multi-pin Plug Insulators

2017, 31 (05): 98-102 ; DOI: 10.19491/j.issn.1001-9278.2017.05.018

Abstract ( 508 )

The analysis of warpage occurring in the injection molding process for a multi-pin plug insulator was performed by using a Moldflow software to determine maximum number and location of mold gate. On the basis of the characteristics of multi-hole structure, small hole size and high precision of hole position in plastic insulator parts, the injection mold was designed by adopting a series of new techniques including a twice fixing core for mold, a combination process for core-retainer plate and precise positioning for the fixed and movable mold cores to ensure a position accuracy for the holes. The results indicated that the total shrinkage deformation and shrinkage from each direction were optimized when using a side and sub gate with a short edge. It was confirmed by practical production that the designed mould had a reasonable structure and could be used to produce plastic parts with a high quality.

Design of Stacked-hot-runner-type Injection Molds for Outlet Joints of Cylinder Heads

2017, 31 (05): 103-108 ; DOI: 10.19491/j.issn.1001-9278.2017.05.019

Abstract ( 443 )

According to the product and technical requests for the injection-molded outlet joints of cylinder heads provided by an enterprise, the injuction mould used for the production of this outlet joint was designed by adopting a stacked-hot-runner structure, and the feasibility of designed scheme was confirmed through a molding simulation using a Moldflow software. Furthermore, the side core-pushing and side parting mechanisms, a stacked-hot-runner system, a two-step ejection mechanism and electrical heat and temperature control systems were designed. The mould has been used for the practical production and proved that it has reasonable structure.